Emotional Intelligence, Academic Motivation, and Achievement among Health Science Students in Saudi Arabia: A Self-Deterministic Approach

Mahrous, Rasha Mohammed,Bugis, Bussma Ahmed,Sayed, Samiha Hamdi 한국간호과학회 2023 Journal of Korean Academy of Nursing Vol.53 No.6

Utilization of Cement Kiln Dust in Industry Cement Bricks

Mahrous Ali Mohammed Ali,양형식 한국자원공학회 2011 Geosystem engineering Vol.14 No.1

Solid waste management is one of the major environmental concerns around the world. Cement kiln dust (CKD), also known as by-pass dust, is a by-product of cement manufacturing. The environmental concerns related to Portland cement production, specifically emissions to the atmosphere and the disposals of CKD are becoming progressively significant. CKD is fine-grained, particulate material chiefly composed of oxidized, anhydrous, micron-sized particles collected from electrostatic precipitators during the high temperature production of clinker. Some of the cement kiln dust that is generated is reused in the cement plant and some is landfilled. Recently, there have been trends of utilizing it for soil stabilization and treatment of sewage. The beneficial uses of CKD include serving as filler material in highway construction and maintenance and as a component of cement mortar/concrete. Also, attempts have been made to use it to make cement bricks for use in industrial construction, and this paper provides a review of the results and issues associated with this use. The paper reports the results of tests conducted by the authors to investigate the properties of cement-CKD combinations and the extent to which such combination are used to manufacture cement bricks. All of the properties of the bricks that were tested found to be satisfactory according to the Egyptian Code, e.g., compressive strength was satisfactory in the range of 59.9 to 213.3kg/cm2, water absorption was directly increased from 3.8 to 5.9% and the density ranged between 2.1 and 2.2 gm/cm3 with different percentage of cement kiln dust from 0 to 40%. In comparing the different types of bricks and their costs, this study found that cement bricks that include CKD as a component had acceptable properties and cost far less than other types of bricks. In addition, the use of CKD in the bricks precludes the need to dispose large quantities of this material in landfill.

Design and Implementation of a Multi Level Three-Phase Inverter with Less Switches and Low Output Voltage Distortion

Mahrous E. Ahmed,Saad Mekhilef 전력전자학회 2009 JOURNAL OF POWER ELECTRONICS Vol.9 No.4

This paper proposes and describes the design and operational principles of a three-phase three-level nine switch voltage source inverter. The proposed topology consists of three bi-directional switches inserted between the source and the full-bridge power switches of the classical three-phase inverter. As a result, a three-level output voltage waveform and a significant suppression of load harmonics contents are obtained at the inverter output. The harmonics content of the proposed multilevel inverter can be reduced by half compared with two-level inverters. A Fourier analysis of the output waveform is performed and the design is optimized to obtain the minimum total harmonic distortion. The full-bridge power switches of the classical three-phase inverter operate at the line frequency of 50㎐, while the auxiliary circuit switches operate at twice the line frequency. To validate the proposed topology, both simulation and analysis have been performed. In addition, a prototype has been designed, implemented and tested. Selected simulation and experimental results have been provided.

A New Single-Phase Asymmetrical Cascaded Multilevel DC-Link Inverter

Mahrous Ahmed,Essam Hendawi 전력전자학회 2016 JOURNAL OF POWER ELECTRONICS Vol.16 No.4

This paper presents a new single-phase asymmetrical cascaded multilevel DC-link inverter. The proposed inverter comprises two stages. The main stage of the inverter consists of multiple similar cells, each of which is a half-bridge inverter consisting of two switches and a single DC source. All cells are connected in a cascaded manner with a fixed neutral point. The DC source values are not made equal to increase the performance of the inverter. The second circuit is a folded cascaded H-bridge circuit operating at a line frequency. One of the main advantages of this proposed topology is that it is a modular type and can thus be extended to high stages without changing the configuration of the main stage circuit. Two control schemes, namely, low switching with selective harmonic elimination and sinusoidal pulse width modulation, are employed to validate the proposed topology. The detailed approach of each control scheme and switching pulses are discussed in detail. A 150W prototype of the proposed system is implemented in the laboratory to verify the validity of the proposed topology.

Breast Metastasis from Renal Cell Carcinoma: Rare Initial Presentation of Disease Recurrence after 5 Years

Mervat Mahrous,Walid Al Morsy,Ahmed Al-Hujaily,Sameerah AL-Sulimani 한국유방암학회 2012 Journal of breast cancer Vol.15 No.2

Metastasis to the breast from extra-mammary tumors is rare with only a few sporadic cases reported. We present a 58-yearold female patient diagnosed with renal cell carcinoma. Five years ago she had a radical nephrectomy and was free of disease, then discovered solitary breast mass following self-examination. The patient presented to the breast clinic for evaluation whereupon the breast mass was identified on physical and radiological examinations. Fine needle aspiration was diagnostic of metastatic renal cell carcinoma and subsequent imaging studies demonstrated multiple pulmonary deposits and recurrent renal mass in the tumor bed of the diseased site. In a multidisciplinary clinic, the patient was elected for excision biopsy followed by systemic tyrosine kinase inhibitor therapy. Six months later she had brain metastasis and received whole brain irradiation followed by palliative therapy. We are presenting this rare case with the aim of increasing awareness of breast secondaries.

Dielectric relaxation of chlorinated polyvinyl chloride (CPVC) stabilized with cyanoguanidine

Salah Mahrous,Taha A. Hanfy,Maged S. Sobhyv 한국물리학회 2007 Current Applied Physics Vol.7 No.6

Dielectric spectra of CPVC stabilized with cyanoguanidine were studied in the temperature range 300450 K and frequency range10 kHz to 1 MHz. In these conditions, only one clear dielectric relaxation band (a-type) associated with dipolar polarization wasobserved. Dielectric losses was found to directly proportional to the number of dipoles (N) which reects the orientational distributionof polymer chains in the amorphous region, at which dielectric losses concerned. Calculations of the dielectric modulusM0(T) at lowtemperature indicate that there is a role of the electrode polarization in the relaxation process. Dielectric loss data were used to calculatethe activation enthalpy by two dierent methods, the obtained value was. 450 kJ/mol.

Poole -Frenkel conduction in polyvinyl chloride stabilized with dibutylin laurate-maleate

Salah Mahrous,T.A.Hanfy 한국물리학회 2004 Current Applied Physics Vol.4 No.5

Electric conduction in PVC-stabilized with dibutylin lauratemaleate has been investigated. In the low voltage region, theconduction was found to be due to thermally generated carriers. At higher voltages, the conduction mechanism was identied asPooleFrenkel type. The charge carriers injected on the polymer surface from the electrodes was found to disappear and become thesource of thermally stimulated discharge (TSD) current.

Design and Implementation of a Multi Level Three-Phase Inverter with Less Switches and Low Output Voltage Distortion

Ahmed, Mahrous E.,Mekhilef, Saad The Korean Institute of Power Electronics 2009 JOURNAL OF POWER ELECTRONICS Vol.9 No.4

This paper proposes and describes the design and operational principles of a three-phase three-level nine switch voltage source inverter. The proposed topology consists of three bi-directional switches inserted between the source and the full-bridge power switches of the classical three-phase inverter. As a result, a three-level output voltage waveform and a significant suppression of load harmonics contents are obtained at the inverter output. The harmonics content of the proposed multilevel inverter can be reduced by half compared with two-level inverters. A Fourier analysis of the output waveform is performed and the design is optimized to obtain the minimum total harmonic distortion. The full-bridge power switches of the classical three-phase inverter operate at the line frequency of 50Hz, while the auxiliary circuit switches operate at twice the line frequency. To validate the proposed topology, both simulation and analysis have been performed. In addition, a prototype has been designed, implemented and tested. Selected simulation and experimental results have been provided.

A New Single-Phase Asymmetrical Cascaded Multilevel DC-Link Inverter

Ahmed, Mahrous,Hendawi, Essam The Korean Institute of Power Electronics 2016 JOURNAL OF POWER ELECTRONICS Vol.16 No.4

This paper presents a new single-phase asymmetrical cascaded multilevel DC-link inverter. The proposed inverter comprises two stages. The main stage of the inverter consists of multiple similar cells, each of which is a half-bridge inverter consisting of two switches and a single DC source. All cells are connected in a cascaded manner with a fixed neutral point. The DC source values are not made equal to increase the performance of the inverter. The second circuit is a folded cascaded H-bridge circuit operating at a line frequency. One of the main advantages of this proposed topology is that it is a modular type and can thus be extended to high stages without changing the configuration of the main stage circuit. Two control schemes, namely, low switching with selective harmonic elimination and sinusoidal pulse width modulation, are employed to validate the proposed topology. The detailed approach of each control scheme and switching pulses are discussed in detail. A 150W prototype of the proposed system is implemented in the laboratory to verify the validity of the proposed topology.

Analysis of FHIT Gene Methylation in Egyptian Breast Cancer Women: Association with Clinicopathological Features

Zaki, Seham Mahrous,Abdel-Azeez, Hala A.,El Nagar, Mona Roshdy,Metwally, Khaled Abdel-Aziz,Ahmed, Marwa M. Samir S. Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.3

Background: Fragile histidine triad (FHIT) gene is a tumor suppressor gene which involved in breast cancer pathogenesis. Epigenetics alterations in FHIT contributes to tumorigenesis of breast cancer. Objective: Our objective was to study FHIT promoter region hypermethylation in Egyptian breast cancer patients and its association with clinicopathological features. Materials and Methods: Methylation-specific polymerase chain reaction was performed to study the hypermethylation of FHIT promoter region in 20 benign breast tissues and 30 breast cancer tissues. Results: The frequency of hypermethylation of FHIT promoter region was significantly increased in breast cancer patients compared to bengin breast disease patients. The Odd's ratio (95%CI) of development of breast cancer in individuals with FHIT promoter hypermethylation (MM) was 11.0 (1.22-250.8). There were also significant associations between FHIT promoter hypermethylation and estrogen, progesterone receptors negativity, tumor stage and nodal involvment in breast cancer pateints. Conclusions: Our results support an association between FHIT promotor hypermethylation and development of breast cancer in Egyptian breast cancer patients. FHIT promoter hypermethylation is associated with some poor prognostic features of breast cancer.